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<title>无标题文档</title>
<script>
	function doAdd(num1, num2){
		arguments[1]=20;
		console.log(arguments[0]);//10
		console.log(arguments[1]);//20
		
		console.log(num1);//10
		console.log(num2);//undefined 原因：argument.length==1，(由传入的实参决定的)只有实参arguments[0]反映到对应的形参num1上面，arguments[1]不反映到num2
	};
	//doAdd(10);
	doAdd(30, 10);
	
</script>
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